(a) Technical Field
The present disclosure relates to a control method for a vehicle with a DCT (Dual Clutch Transmission), and more particularly, to a control method for a vehicle with a DCT capable of controlling a clutch of the DCT when an ISG (Idle Stop & Go) function is implemented by the vehicle mounted with the DCT.
(b) Background Art
Recently, a DCT with good fuel efficiency has gained popularity and further trials for maximizing the fuel efficiency have actively been made by adding an ISG function as another operation for improving fuel efficiency.
Since the DCT does not use a torque converter used as an accelerator in an AT (Automatic Transmission), the DCT accelerates with a slip control of the clutch and thus a vibration property is not good when a vehicle starts.
Recently, as a transmission to be mounted on environmental-friendly vehicles, a DCT (Dual Clutch Transmission) is spotlighted, and as another item to improve fuel efficiency, many efforts are directed to maximizing fuel efficiency of a vehicle by adding the ISG (Idle Stop & Go) function.
The DCT has a defect in that a vehicle is accelerated by slip control of a clutch and thus vibration characteristics when starting the vehicle are poor, because it does not use a torque converter used as an accelerator in an AT (Automatic Transmission).
In order to overcome the defect, a DMF (Dual Mass Flywheel) is disposed between an engine and a transmission to be able to reduce a change in torque and dampen vibration. Further, in the ISG, in a technology for preventing unnecessary fuel consumption due to idling of an engine by making the engine automatically stop when a vehicle is stopped, it is an important technological subject to improve a shock in a vehicle when an engine stops, and the start speed when the engine is restarted.
In the combination of the DCT and the ISG, there is a need for a control technology which reduces a shock in a vehicle and quickly stops the engine when the engine stops with an entry into the ISG, because there is no torque converter between the engine and the transmission, unlike the AT.
In particular, because the DCT is equipped with a DMF, it has a problem in that the engine does not quickly stop, even though fuel supply is stopped to stop the engine.
That is, as shown in FIG. 1, the engine speed is slowly reduced by an influence of the DMF when an engine stops for the ISG in the DCT, and the slow reduction of the engine speed may be a little advantageous in terms of reducing vibration or a shock in a vehicle; however, a driver has to wait for the engine to completely stop for engagement of a ring gear of the engine and a gear of a starter motor, in order to restart the engine for starting the vehicle. Therefore, there is a problem in that a restart of the vehicle is delayed.
The description provided above as related art of the present disclosure is intended only to help understand the background of the present disclosure and should not be construed as being known by those having ordinary skill in the art.